Many functions of modern devices in automotive, consumer and industrial applications, such as converting electrical energy and driving an electric motor or an electric machine, rely on semiconductor devices. For example, Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) and diodes have been used for various applications including, but not limited to switches in power supplies and power converters.
Many of such semiconductor devices used in power electronics are diodes or comprise diode structures such as the diode structures of reverse conducting IGBTs or the built-in body diodes of MOSFETs.
Often, the anode of such diode structures has a relatively low doping level, i.e., the emitter efficiency is kept low in order to form the charge carrier concentration in a way that is advantageous for the dynamic switching behavior, such as soft recovery. At the same time, it is sometimes desirable to ensure a low ohmic contact between the anode and, e.g., a front side metallization, which is generally challenging, given the low doping level of the anode.